LAS VEGAS — In the latest installment of their simmering rivalry, Gonzaga again did to Saint Mary’s what it had done the previous two games this season.

It was herky-jerky and not in the least aesthetic, but the Zags controlled the Gaels in the semifinals of the West Coast Conference Tournament Monday night, winning 70-54.

The victory puts them in the WCC final against Brigham Young (23-10) a 79-77 winner in overtime against San Francisco in the other semifinal, and all but assures a 16th consecutive trip to the NCAA tournament, inasmuch as the Gaels are ranked No. 60 in the latest RPI computer rankings and BYU is in the top 50.

Gonzaga (27-6) won the first two games against Saint Mary’s by a total of 50 points, and by midway through the second half Monday, led this one by 18. On a night when their big guys struggled, the Zags were led by guards Gary Bell Jr. (14 points) and David Stockton (21 points), who managed pace and hit 12 of their first 17 shots combined.

Down 31-20 at half, Saint Mary’s made a brief surge after intermission, creeping to 33-27 after its first three of the game, by guard Kerry Carter. But back came the Zags, and Kevin Pangos’ first shot attempt of the game caught all of the rim before going down, a three.

Bell, a key figure all evening, drove for a score, and after Stockton nudged the ball away from Paul McCoy, Stockton banked in his own runner for a 40-27 Zags lead at the first television timeout of the second half.

Saint Mary’s closed to 40-31 before the Zags put the hammer down. Stockton, effective in this tournament driving to the hole, did it again, and was fouled. He missed the free throw, but the Zags retained possession and Bell, out of Kentridge High, rang up a three to make it 45-31 with 14:32 left.

In a first half without rhythm, Gonzaga did a methodical trudge to a 13-4 lead in the first eight minutes, as Saint Mary’s offensive problems against GU this season continued.

The Gaels, who had just 27 field goals in the first two games — both blowout victories by Gonzaga — added a mere three in the first 12 minutes, making it 30 in 92 minutes in 2013-14, or less than one per three minutes. Bell gave the Zags an early boost, hitting a corner trey for a 7-2 lead, and moments later, driving for consecutive baskets to push the GU lead to 13-4.

Saint Mary’s got much improved play from center Brad Waldow (just four of 16 field goals in the first two games), but had little to complement him. Waldow hit all four of his attempts for nine points, but the Gaels combined for only five field goals around him before intermission.